Pub Date : 2022-11-17DOI: 10.1007/s12200-022-00050-3
Xianglang Sun, Zonglong Zhu, Zhong'an Li
Inverted perovskite solar cells (PVSCs) have recently made exciting progress, showing high power conversion efficiencies (PCEs) of 25% in single-junction devices and 30.5% in silicon/perovskite tandem devices. The hole transporting material (HTM) in an inverted PVSC plays an important role in determining the device performance, since it not only extracts/transports holes but also affects the growth and crystallization of perovskite film. Currently, polymer and self-assembled monolayer (SAM) have been considered as two types of most promising HTM candidates for inverted PVSCs owing to their high PCEs, high stability and adaptability to large area devices. In this review, recent encouraging progress of high-performance polymer and SAM-based HTMs is systematically reviewed and summarized, including molecular design strategies and the correlation between molecular structure and device performance. We hope this review can inspire further innovative development of HTMs for wide applications in highly efficient and stable inverted PVSCs and the tandem devices.
{"title":"Recent advances in developing high-performance organic hole transporting materials for inverted perovskite solar cells.","authors":"Xianglang Sun, Zonglong Zhu, Zhong'an Li","doi":"10.1007/s12200-022-00050-3","DOIUrl":"https://doi.org/10.1007/s12200-022-00050-3","url":null,"abstract":"<p><p>Inverted perovskite solar cells (PVSCs) have recently made exciting progress, showing high power conversion efficiencies (PCEs) of 25% in single-junction devices and 30.5% in silicon/perovskite tandem devices. The hole transporting material (HTM) in an inverted PVSC plays an important role in determining the device performance, since it not only extracts/transports holes but also affects the growth and crystallization of perovskite film. Currently, polymer and self-assembled monolayer (SAM) have been considered as two types of most promising HTM candidates for inverted PVSCs owing to their high PCEs, high stability and adaptability to large area devices. In this review, recent encouraging progress of high-performance polymer and SAM-based HTMs is systematically reviewed and summarized, including molecular design strategies and the correlation between molecular structure and device performance. We hope this review can inspire further innovative development of HTMs for wide applications in highly efficient and stable inverted PVSCs and the tandem devices.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"46"},"PeriodicalIF":5.4,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756258/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10528945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-14DOI: 10.1007/s12200-022-00045-0
Pan Jiang, Peili Li, Yiming Fan
Broadband optical frequency comb (OFC) generation based on a single electro-absorption modulator (EAM) is proposed. The EAM is driven by a radio frequency (RF) multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit. Thus the number of comb-lines of the generated OFC can be increased. A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established, and the performance of the OFC is analyzed by using OptiSystem software. The results show that, the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal. The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal. Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC. The amplitude of the RF source signal had little impact on the flatness of the OFC and the average OFC power. The scheme developed is not only simple and low-cost, but also can produce a large number of comb-lines.
{"title":"Broadband optical frequency comb generation based on single electro-absorption modulation driven by radio frequency coupled signals.","authors":"Pan Jiang, Peili Li, Yiming Fan","doi":"10.1007/s12200-022-00045-0","DOIUrl":"https://doi.org/10.1007/s12200-022-00045-0","url":null,"abstract":"<p><p>Broadband optical frequency comb (OFC) generation based on a single electro-absorption modulator (EAM) is proposed. The EAM is driven by a radio frequency (RF) multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit. Thus the number of comb-lines of the generated OFC can be increased. A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established, and the performance of the OFC is analyzed by using OptiSystem software. The results show that, the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal. The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal. Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC. The amplitude of the RF source signal had little impact on the flatness of the OFC and the average OFC power. The scheme developed is not only simple and low-cost, but also can produce a large number of comb-lines.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"45"},"PeriodicalIF":5.4,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756252/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9080164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-10DOI: 10.1007/s12200-022-00046-z
Yalei Duan, Runda Guo, Yaxiong Wang, Kaiyuan Di, Lei Wang
Highly efficient blue fluorescent materials have recently attracted great interest for organic light-emitting diode (OLED) application. Here, two new pyrene based organic molecules consisting of a highly rigid skeleton, namely SPy and DPy, are developed. These two blue light emitters exhibit excellent thermal stability. The experiment reveals that the full-width at half-maximum (FWHM) of the emission spectrum can be tuned by introducing different amounts of 9,9-diphenyl-N-phenyl-9H-fluoren-2-amine on pyrene units. The FWHM of the emission spectrum is only 37 nm in diluted toluene solution for DPy. Furthermore, highly efficient blue OLEDs are obtained by thermally activated delayed fluorescence (TADF) sensitization strategy. The blue fluorescent OLEDs utilizing DPy as emitters achieve a maximum external quantum efficiency (EQE) of 10.4% with the electroluminescence (EL) peak/FWHM of 480 nm/49 nm. Particularly, the EQE of DPy-based device is boosted from 2.6% in non-doped device to 10.4% in DMAc-DPS TADF sensitized fluorescence (TSF) device, which is a 400% enhancement. Therefore, this work demonstrates that the TSF strategy is promising for highly efficient fluorescent OLEDs application in wide-color-gamut display field.
{"title":"A sensitization strategy for highly efficient blue fluorescent organic light-emitting diodes.","authors":"Yalei Duan, Runda Guo, Yaxiong Wang, Kaiyuan Di, Lei Wang","doi":"10.1007/s12200-022-00046-z","DOIUrl":"https://doi.org/10.1007/s12200-022-00046-z","url":null,"abstract":"<p><p>Highly efficient blue fluorescent materials have recently attracted great interest for organic light-emitting diode (OLED) application. Here, two new pyrene based organic molecules consisting of a highly rigid skeleton, namely SPy and DPy, are developed. These two blue light emitters exhibit excellent thermal stability. The experiment reveals that the full-width at half-maximum (FWHM) of the emission spectrum can be tuned by introducing different amounts of 9,9-diphenyl-N-phenyl-9H-fluoren-2-amine on pyrene units. The FWHM of the emission spectrum is only 37 nm in diluted toluene solution for DPy. Furthermore, highly efficient blue OLEDs are obtained by thermally activated delayed fluorescence (TADF) sensitization strategy. The blue fluorescent OLEDs utilizing DPy as emitters achieve a maximum external quantum efficiency (EQE) of 10.4% with the electroluminescence (EL) peak/FWHM of 480 nm/49 nm. Particularly, the EQE of DPy-based device is boosted from 2.6% in non-doped device to 10.4% in DMAc-DPS TADF sensitized fluorescence (TSF) device, which is a 400% enhancement. Therefore, this work demonstrates that the TSF strategy is promising for highly efficient fluorescent OLEDs application in wide-color-gamut display field.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"44"},"PeriodicalIF":5.4,"publicationDate":"2022-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756245/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10528943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal halide perovskites (MHPs) have demonstrated excellent performances in detection of X-rays and gamma-rays. Most studies focus on improving the sensitivity of single-pixel MHP detectors. However, little work pays attention to the dark current, which is crucial for the back-end circuit integration. Herein, the requirement of dark current is quantitatively evaluated as low as 10-9 A/cm2 for X-ray imagers integrated on pixel circuits. Moreover, through the semiconductor device analysis and simulation, we reveal that the main current compositions of thick perovskite X-ray detectors are the thermionic-emission current (JT) and the generation-recombination current (Jg-r). The typical observed failures of p-n junctions in thick detectors are caused by the high generation-recombination current due to the band mismatch and interface defects. This work provides a deep insight into the design of high sensitivity and low dark current perovskite X-ray detectors.
{"title":"Dark current modeling of thick perovskite X-ray detectors.","authors":"Shan Zhao, Xinyuan Du, Jincong Pang, Haodi Wu, Zihao Song, Zhiping Zheng, Ling Xu, Jiang Tang, Guangda Niu","doi":"10.1007/s12200-022-00044-1","DOIUrl":"https://doi.org/10.1007/s12200-022-00044-1","url":null,"abstract":"<p><p>Metal halide perovskites (MHPs) have demonstrated excellent performances in detection of X-rays and gamma-rays. Most studies focus on improving the sensitivity of single-pixel MHP detectors. However, little work pays attention to the dark current, which is crucial for the back-end circuit integration. Herein, the requirement of dark current is quantitatively evaluated as low as 10<sup>-9</sup> A/cm<sup>2</sup> for X-ray imagers integrated on pixel circuits. Moreover, through the semiconductor device analysis and simulation, we reveal that the main current compositions of thick perovskite X-ray detectors are the thermionic-emission current (J<sub>T</sub>) and the generation-recombination current (J<sub>g-r</sub>). The typical observed failures of p-n junctions in thick detectors are caused by the high generation-recombination current due to the band mismatch and interface defects. This work provides a deep insight into the design of high sensitivity and low dark current perovskite X-ray detectors.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"43"},"PeriodicalIF":5.4,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756221/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10530601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-28DOI: 10.1007/s12200-022-00043-2
Masumeh Sarkhoush, Hassan Rasooli Saghai, Hadi Soofi
Recent experiments suggest graphene-based materials as candidates for use in future electronic and optoelectronic devices. In this study, we propose a new multilayer quantum dot (QD) superlattice (SL) structure with graphene as the core and silicon (Si) as the shell of QD. The Slater-Koster tight-binding method based on Bloch theory is exploited to investigate the band structure and energy states of the graphene/Si QD. Results reveal that the graphene/Si QD is a type-I QD and the ground state is 0.6 eV above the valance band. The results also suggest that the graphene/Si QD can be potentially used to create a sub-bandgap in all Si-based intermediate-band solar cells (IBSC). The energy level hybridization in a SL of graphene/Si QDs is investigated and it is observed that the mini-band formation is under the influence of inter-dot spacing among QDs. To evaluate the impact of the graphene/Si QD SL on the performance of Si-based solar cells, we design an IBSC based on the graphene/Si QD (QDIBSC) and calculate its short-circuit current density (Jsc) and carrier generation rate (G) using the 2D finite difference time domain (FDTD) method. In comparison with the standard Si-based solar cell which records Jsc = 16.9067 mA/cm2 and G = 1.48943 × 1028 m-3⋅s-1, the graphene/Si QD IBSC with 2 layers of QDs presents Jsc = 36.4193 mA/cm2 and G = 7.94192 × 1028 m-3⋅s-1, offering considerable improvement. Finally, the effects of the number of QD layers (L) and the height of QD (H) on the performance of the graphene/Si QD IBSC are discussed.
{"title":"Design and simulation of type-I graphene/Si quantum dot superlattice for intermediate-band solar cell applications.","authors":"Masumeh Sarkhoush, Hassan Rasooli Saghai, Hadi Soofi","doi":"10.1007/s12200-022-00043-2","DOIUrl":"https://doi.org/10.1007/s12200-022-00043-2","url":null,"abstract":"<p><p>Recent experiments suggest graphene-based materials as candidates for use in future electronic and optoelectronic devices. In this study, we propose a new multilayer quantum dot (QD) superlattice (SL) structure with graphene as the core and silicon (Si) as the shell of QD. The Slater-Koster tight-binding method based on Bloch theory is exploited to investigate the band structure and energy states of the graphene/Si QD. Results reveal that the graphene/Si QD is a type-I QD and the ground state is 0.6 eV above the valance band. The results also suggest that the graphene/Si QD can be potentially used to create a sub-bandgap in all Si-based intermediate-band solar cells (IBSC). The energy level hybridization in a SL of graphene/Si QDs is investigated and it is observed that the mini-band formation is under the influence of inter-dot spacing among QDs. To evaluate the impact of the graphene/Si QD SL on the performance of Si-based solar cells, we design an IBSC based on the graphene/Si QD (QDIBSC) and calculate its short-circuit current density (J<sub>sc</sub>) and carrier generation rate (G) using the 2D finite difference time domain (FDTD) method. In comparison with the standard Si-based solar cell which records J<sub>sc</sub> = 16.9067 mA/cm<sup>2</sup> and G = 1.48943 × 10<sup>28</sup> m<sup>-3</sup>⋅s<sup>-1</sup>, the graphene/Si QD IBSC with 2 layers of QDs presents J<sub>sc</sub> = 36.4193 mA/cm<sup>2</sup> and G = 7.94192 × 10<sup>28</sup> m<sup>-3</sup>⋅s<sup>-1</sup>, offering considerable improvement. Finally, the effects of the number of QD layers (L) and the height of QD (H) on the performance of the graphene/Si QD IBSC are discussed.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"42"},"PeriodicalIF":5.4,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756208/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9094889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-11DOI: 10.1007/s12200-022-00041-4
Yu Xiao, Junyu Qu, Ziyu Luo, Ying Chen, Xin Yang, Danliang Zhang, Honglai Li, Biyuan Zheng, Jiali Yi, Rong Wu, Wenxia You, Bo Liu, Shula Chen, Anlian Pan
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted extensive attention due to their unique electronic and optical properties. In particular, TMDs can be flexibly combined to form diverse vertical van der Waals (vdWs) heterostructures without the limitation of lattice matching, which creates vast opportunities for fundamental investigation of novel optoelectronic applications. Here, we report an atomically thin vertical p-n junction WSe2/MoS2 produced by a chemical vapor deposition method. Transmission electron microscopy and steady-state photoluminescence experiments reveal its high quality and excellent optical properties. Back gate field effect transistor (FET) constructed using this p-n junction exhibits bipolar behaviors and a mobility of 9 cm2/(V·s). In addition, the photodetector based on MoS2/WSe2 heterostructures displays outstanding optoelectronic properties (R = 8 A/W, D* = 2.93 × 1011 Jones, on/off ratio of 104), which benefited from the built-in electric field across the interface. The direct growth of TMDs p-n vertical heterostructures may offer a novel platform for future optoelectronic applications.
{"title":"Van der Waals epitaxial growth and optoelectronics of a vertical MoS<sub>2</sub>/WSe<sub>2</sub> p-n junction.","authors":"Yu Xiao, Junyu Qu, Ziyu Luo, Ying Chen, Xin Yang, Danliang Zhang, Honglai Li, Biyuan Zheng, Jiali Yi, Rong Wu, Wenxia You, Bo Liu, Shula Chen, Anlian Pan","doi":"10.1007/s12200-022-00041-4","DOIUrl":"https://doi.org/10.1007/s12200-022-00041-4","url":null,"abstract":"<p><p>Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted extensive attention due to their unique electronic and optical properties. In particular, TMDs can be flexibly combined to form diverse vertical van der Waals (vdWs) heterostructures without the limitation of lattice matching, which creates vast opportunities for fundamental investigation of novel optoelectronic applications. Here, we report an atomically thin vertical p-n junction WSe<sub>2</sub>/MoS<sub>2</sub> produced by a chemical vapor deposition method. Transmission electron microscopy and steady-state photoluminescence experiments reveal its high quality and excellent optical properties. Back gate field effect transistor (FET) constructed using this p-n junction exhibits bipolar behaviors and a mobility of 9 cm<sup>2</sup>/(V·s). In addition, the photodetector based on MoS<sub>2</sub>/WSe<sub>2</sub> heterostructures displays outstanding optoelectronic properties (R = 8 A/W, D* = 2.93 × 10<sup>11</sup> Jones, on/off ratio of 10<sup>4</sup>), which benefited from the built-in electric field across the interface. The direct growth of TMDs p-n vertical heterostructures may offer a novel platform for future optoelectronic applications.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"41"},"PeriodicalIF":5.4,"publicationDate":"2022-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756242/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9080171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-29DOI: 10.1007/s12200-022-00042-3
Pan Li, Zhihui Sun, Rui Wang, Yuchen Gong, Yingting Zhou, Yuwei Wang, Xiaojuan Liu, Xianjun Zhou, Ju Ouyang, Mingzhi Chen, Chong Hou, Min Chen, Guangming Tao
Color-changeable fibers can provide diverse functions for intelligent wearable devices such as novel information displays and human-machine interfaces when woven into fabric. This work develops a low-cost, effective, and scalable strategy to produce thermochromic fibers by wet spinning. Through a combination of different thermochromic microcapsules, flexible fibers with abundant and reversible color changes are obtained. These color changes can be clearly observed by the naked eye. It is also found that the fibers exhibit excellent color-changing stability even after 8000 thermal cycles. Moreover, the thermochromic fibers can be fabricated on a large scale and easily woven or implanted into various fabrics with good mechanical performance. Driven by their good mechanical and physical characteristics, applications of thermochromic fibers in dynamic colored display are demonstrated. Dynamic quick response (QR) code display and recognition are successfully realized with thermochromic fabrics. This work well confirms the potential applications of thermochromic fibers in smart textiles, wearable devices, flexible displays, and human-machine interfaces.
{"title":"Flexible thermochromic fabrics enabling dynamic colored display.","authors":"Pan Li, Zhihui Sun, Rui Wang, Yuchen Gong, Yingting Zhou, Yuwei Wang, Xiaojuan Liu, Xianjun Zhou, Ju Ouyang, Mingzhi Chen, Chong Hou, Min Chen, Guangming Tao","doi":"10.1007/s12200-022-00042-3","DOIUrl":"https://doi.org/10.1007/s12200-022-00042-3","url":null,"abstract":"<p><p>Color-changeable fibers can provide diverse functions for intelligent wearable devices such as novel information displays and human-machine interfaces when woven into fabric. This work develops a low-cost, effective, and scalable strategy to produce thermochromic fibers by wet spinning. Through a combination of different thermochromic microcapsules, flexible fibers with abundant and reversible color changes are obtained. These color changes can be clearly observed by the naked eye. It is also found that the fibers exhibit excellent color-changing stability even after 8000 thermal cycles. Moreover, the thermochromic fibers can be fabricated on a large scale and easily woven or implanted into various fabrics with good mechanical performance. Driven by their good mechanical and physical characteristics, applications of thermochromic fibers in dynamic colored display are demonstrated. Dynamic quick response (QR) code display and recognition are successfully realized with thermochromic fabrics. This work well confirms the potential applications of thermochromic fibers in smart textiles, wearable devices, flexible displays, and human-machine interfaces.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"40"},"PeriodicalIF":5.4,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756210/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10530609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Formamidinium lead triiodide (FAPbI3) perovskite quantum dots (PQDs) show great advantages in photovoltaic applications due to their ideal bandgap energy, high stability and solution processability. The anti-solvent used for the post-treatment of FAPbI3 PQD solid films significantly affects the surface chemistry of the PQDs, and thus the vacancies caused by surface ligand removal inhibit the optoelectronic properties and stability of PQDs. Here, we study the effects of different anti-solvents with different polarities on FAPbI3 PQDs and select a series of organic molecules for surface passivation of PQDs. The results show that methyl acetate could effectively remove surface ligands from the PQD surface without destroying its crystal structure during the post-treatment. The benzamidine hydrochloride (PhFACl) applied as short ligands of PQDs during the post-treatment could fill the A-site and X-site vacancies of PQDs and thus improve the electronic coupling of PQDs. Finally, the PhFACl-based PQD solar cell (PQDSC) achieves a power conversion efficiency of 6.4%, compared to that of 4.63% for the conventional PQDSC. This work provides a reference for insights into the surface passivation of PQDs and the improvement in device performance of PQDSCs.
{"title":"Ligand exchange engineering of FAPbI<sub>3</sub> perovskite quantum dots for solar cells.","authors":"Wentao Fan, Qiyuan Gao, Xinyi Mei, Donglin Jia, Jingxuan Chen, Junming Qiu, Qisen Zhou, Xiaoliang Zhang","doi":"10.1007/s12200-022-00038-z","DOIUrl":"https://doi.org/10.1007/s12200-022-00038-z","url":null,"abstract":"<p><p>Formamidinium lead triiodide (FAPbI<sub>3</sub>) perovskite quantum dots (PQDs) show great advantages in photovoltaic applications due to their ideal bandgap energy, high stability and solution processability. The anti-solvent used for the post-treatment of FAPbI<sub>3</sub> PQD solid films significantly affects the surface chemistry of the PQDs, and thus the vacancies caused by surface ligand removal inhibit the optoelectronic properties and stability of PQDs. Here, we study the effects of different anti-solvents with different polarities on FAPbI<sub>3</sub> PQDs and select a series of organic molecules for surface passivation of PQDs. The results show that methyl acetate could effectively remove surface ligands from the PQD surface without destroying its crystal structure during the post-treatment. The benzamidine hydrochloride (PhFACl) applied as short ligands of PQDs during the post-treatment could fill the A-site and X-site vacancies of PQDs and thus improve the electronic coupling of PQDs. Finally, the PhFACl-based PQD solar cell (PQDSC) achieves a power conversion efficiency of 6.4%, compared to that of 4.63% for the conventional PQDSC. This work provides a reference for insights into the surface passivation of PQDs and the improvement in device performance of PQDSCs.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"39"},"PeriodicalIF":5.4,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756204/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10528944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Covalent organic frameworks (COFs) are one class of porous materials with permanent porosity and regular channels, and have a covalent bond structure. Due to their interesting characteristics, COFs have exhibited diverse potential applications in many fields. However, some applications require the frameworks to possess high structural stability, excellent crystallinity, and suitable pore size. COFs based on β-ketoenamine and imines are prepared through the irreversible enol-to-keto tautomerization. These materials have high crystallinity and exhibit high stability in boiling water, with strong resistance to acids and bases, resulting in various possible applications. In this review, we first summarize the preparation methods for COFs based on β-ketoenamine, in the form of powders, films and foams. Then, the effects of different synthetic methods on the crystallinity and pore structure of COFs based on β-ketoenamine are analyzed and compared. The relationship between structures and different applications including fluorescence sensors, energy storage, photocatalysis, electrocatalysis, batteries and proton conduction are carefully summarized. Finally, the potential applications, large-scale industrial preparation and challenges in the future are presented.
{"title":"Highly stable β-ketoenamine-based covalent organic frameworks (COFs): synthesis and optoelectrical applications.","authors":"Yaqin Li, Maosong Liu, Jinjun Wu, Junbo Li, Xianglin Yu, Qichun Zhang","doi":"10.1007/s12200-022-00032-5","DOIUrl":"https://doi.org/10.1007/s12200-022-00032-5","url":null,"abstract":"<p><p>Covalent organic frameworks (COFs) are one class of porous materials with permanent porosity and regular channels, and have a covalent bond structure. Due to their interesting characteristics, COFs have exhibited diverse potential applications in many fields. However, some applications require the frameworks to possess high structural stability, excellent crystallinity, and suitable pore size. COFs based on β-ketoenamine and imines are prepared through the irreversible enol-to-keto tautomerization. These materials have high crystallinity and exhibit high stability in boiling water, with strong resistance to acids and bases, resulting in various possible applications. In this review, we first summarize the preparation methods for COFs based on β-ketoenamine, in the form of powders, films and foams. Then, the effects of different synthetic methods on the crystallinity and pore structure of COFs based on β-ketoenamine are analyzed and compared. The relationship between structures and different applications including fluorescence sensors, energy storage, photocatalysis, electrocatalysis, batteries and proton conduction are carefully summarized. Finally, the potential applications, large-scale industrial preparation and challenges in the future are presented.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"38"},"PeriodicalIF":5.4,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756274/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9080166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1007/s12200-022-00039-y
Qi Li, Xiuhua Yuan, Feng Zhou, Zeyu Zhou, Wujie Liu
Water surface wave turbulence is one of the factors affecting the performances of underwater optical wireless communication (UOWC) systems. In our research, a phase-conjugate beam was used to correct the beam distortion and enhance the communication performances when a system is subject to surface wave turbulence. The phase-conjugate beam was generated by a phase-conjugate mirror (PCM), and a turbulence generator was used to generate surface wave turbulence in the experiment. We calculated the beam centroid distribution and the results showed that the phase-conjugate beam had a better propagation performance than the distorted beam at the different water depths. The root mean square (RMS) of the beam centroid for the phase-conjugate beam was 11 times less than that for the distorted beam, which meant that the phase-conjugate beam could effectively correct the beam drift. We further investigated the scintillation index and the signal-to-noise ratio (SNR); the results showed that the phase-conjugate beam was able to reduce the scintillation and an obvious improvement in SNR could be obtained. This research has the potential to be applied in UWC.
{"title":"Application of phase-conjugate beams in beam correction and underwater optical wireless communication subject to surface wave turbulence.","authors":"Qi Li, Xiuhua Yuan, Feng Zhou, Zeyu Zhou, Wujie Liu","doi":"10.1007/s12200-022-00039-y","DOIUrl":"https://doi.org/10.1007/s12200-022-00039-y","url":null,"abstract":"<p><p>Water surface wave turbulence is one of the factors affecting the performances of underwater optical wireless communication (UOWC) systems. In our research, a phase-conjugate beam was used to correct the beam distortion and enhance the communication performances when a system is subject to surface wave turbulence. The phase-conjugate beam was generated by a phase-conjugate mirror (PCM), and a turbulence generator was used to generate surface wave turbulence in the experiment. We calculated the beam centroid distribution and the results showed that the phase-conjugate beam had a better propagation performance than the distorted beam at the different water depths. The root mean square (RMS) of the beam centroid for the phase-conjugate beam was 11 times less than that for the distorted beam, which meant that the phase-conjugate beam could effectively correct the beam drift. We further investigated the scintillation index and the signal-to-noise ratio (SNR); the results showed that the phase-conjugate beam was able to reduce the scintillation and an obvious improvement in SNR could be obtained. This research has the potential to be applied in UWC.</p>","PeriodicalId":12685,"journal":{"name":"Frontiers of Optoelectronics","volume":"15 1","pages":"37"},"PeriodicalIF":5.4,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756247/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10531356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}